I ordered a new master cylinder. My original master cylinder has 1 1/4" stamped on the side of it, my new replacement mc has 1 1/16" on it. They both look the same except for the stamp my oringinal one seem to have a slightly larger diameter on the back where the rubber gaskets are. Will this make a difference if I install the replacement mc. This is the only problem when you buy online using your truck info to order parts. Thanks

 

Your master cylinder must of had a 3/16 larger bore than the one you ordered. I would try to get one with the 1 1/4 bore size like the original.

 

Thanks, I put a 1 1/4" on.